Such “chemical fingerprinting” is a key technique in the search for habitable planets around other stars. As such, the result represents a milestone in the search for life elsewhere in the Universe. More directly, results like this are expected to provide new insight into how planets form.
Image of the HR 8799 system. In the center, the host star HR 8799. Further investigation shows that three of the specks surrounding the star are planets (marked): Starting at 11 o\'clock, clockwise: HR 8799b, HR8799c and HR8799d. The other specks and patterns are artefacts, which are unavoidable in a challenging observation like this one – star and planets are extremely close, and the star is a few thousand times brighter than the planets. The distance from the star to HR 8799c corresponds to 38 times the average Earth-Sun distance. Image credit: MPIA / W. Brandner
The search for life on other planets is one of the most exciting endeavours of modern astronomy. Over the past decade, astronomers have discovered more than 400 exoplanets (that is, planets orbiting stars other than the Sun). In order to judge a planet's habitability, or even detect tell-tale traces of habitation, astronomers need to do more than just detect such planets: They need to find out what the planet – more specifically, its atmosphere – is made of. To this end, they need to obtain the planet's spectrum, a “chemical fingerprint” that can be measured by examining the light received from the planet. Now astronomers have, for the first time, measured the spectrum of an exoplanet orbiting a Sun-like star directly – an important step in the ongoing search.
The research team, which includes three researchers from the Max Planck Institute for Astronomy (MPIA) and two from Canadian universities, studied the planetary system around the bright, very young star HR 8799, 130 light-years from Earth, located within the constellation Pegasus. The planetary system resembles a scaled-up version of our own Solar System and includes three giant planets, which had been detected in 2008 in another study. “Our target was the middle planet of the three, which is roughly ten times more massive than Jupiter and has a temperature of about 800 degrees Celsius,” says team member Carolina Bergfors (MPIA), who participated in the observations as part of her PhD work. The researchers recorded the spectrum using the NACO instrument installed at the European Southern Observatory's Very Large Telescope (VLT) in Chile, in particular its combined camera/spectrograph CONICA, which was developed at the MPIA and at the Max Planck Institute for Extraterrestrial Physics.
As the host star is several thousand times brighter than the planet, and the two are very close, obtaining such a spectrum is an immense feat. Markus Janson of the University of Toronto, lead author of the paper reporting the new findings, explains: “It's like trying to see what a candle is made of, by observing it next to a blinding 300 Watt lamp – from a distance of 2 kilometres [1.3 miles].” Carolina Bergfors (MPIA), whose work on this project is part of her PhD studies, adds: “It took more than five hours of exposure time, but we were able to tease out the planet's spectrum from the host star's much brighter light.”
In time, the astronomers hope that this technique will help them gain a better understanding of how planets form. As a likely first step, they aim to record the spectra of the two other giant planets orbiting HR 8799 – which would represent the first time that astronomers would be able to compare the spectra of three exoplanets that form part of one and the same system. As a much more distant goal, the technique will allow astronomers to examine exoplanets for habitability, or even signs of life.
More immediately, the results pose something of a challenge to current models of the exoplanet's atmosphere. “The features observed in the spectrum are not compatible with current theoretical models,” explains MPIA's Wolfgang Brandner, a co-author of the study. “We need to take into account a more detailed description of the atmospheric dust clouds, or accept that the atmosphere has a different chemical composition than previously assumed.”
Contact informationDr. Wolfgang Brandner (Coauthor)
The team is composed of M. Janson (University of Toronto, Canada), C. Bergfors, M. Goto, W. Brandner (Max-Planck-Institute for Astronomy), and D. Lafrenière (University of Montreal, Canada).
Dr. Markus Pössel | Max-Planck-Institut
NASA's fermi finds possible dark matter ties in andromeda galaxy
22.02.2017 | NASA/Goddard Space Flight Center
Tune your radio: galaxies sing while forming stars
21.02.2017 | Max-Planck-Institut für Radioastronomie
Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...
The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.
The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...
Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...
Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".
Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...
13.02.2017 | Event News
10.02.2017 | Event News
09.02.2017 | Event News
22.02.2017 | Power and Electrical Engineering
22.02.2017 | Life Sciences
22.02.2017 | Innovative Products